1. Field of the Invention
The present invention relates to a belt conveyor for use in an automatic assembling apparatus, designed for conveying parts, and more particularly, to a belt conveyor for use in an apparatus which automatically assembles machines or in an apparatus which automatically conveys electronic parts.
2. Description of Prior Art
Various belt conveyors are known. Among these is one designed to convey mechanical parts to an automatic assembling apparatus comprises a long base member, a first support, a second support, a drive Shaft attached to one end of the base member by the first a support, a driven shaft attached to the other end of the basic member by the second support, and an endless belt wrapped around the drive and the driven shafts. The belt may wave or slip unless a predetermined tension is applied to the belt. The waving or slipping of the belt would impair the supply of parts to the automatic assembling apparatus. In view of this, it is of vital importance to adjust the tension on the endless belt of the belt conveyor.
The longer the belt is used, the more it is elongated. The conventional belt conveyor must therefore be stopped at regular time intervals, and the tension of the belt must be adjusted each time the conveyor is stopped. The tension-adjusting mechanism, which the belt conveyor has, comprises either the second support which can slide on the base member or a portion of the base member which can slide on the other portion In order to increase the tension of the belt to a desired value, the first support or the portion of the base member is moved such that the distance between the drive shaft increases and the driven shaft, thereby tightening up the endless belt, and then is fastened by means of bolts to the base member or the other portion of the base member.
The tension of the belt gradually decreases even after it has been adjusted, as the conveyor belt is used. It may also decrease due to the loosening of the bolts or the loosening of the second support. When the tension decreases too much, the belt conveyor must be stopped, and the bolts must be loosened, the second support must be moved, tightening the endless belt, and the bolts must be tightened again. These steps of adjusting the tension of the belt are very cumbersome and requires many man-hours, particularly in the case where the belt conveyor is located within the automatic assembling apparatus or positioned between complex machines.
Another problem is inherent in the conventional belt conveyor of the type described above. In the case where the conveyor is set in a limited space, Or the tension-adjusting mechanism is located very close to any other component or another belt conveyor, it is impossible to slide the first support or the portion of the base member to increase the distance between the drive shaft and the driven shaft.